The treatment of neuropathic pain ist still a challenge. A new promising therapy is the use of capsaicin on skin.

The investigators first experiences with capsaicin in patients with peripheral nerve injury showed changes in the sensibility, which achieved its maximal extent after four weeks and was regressive, but not completely abolished 1,5 months after application.

In this study the investigators hope to specify, how long and in which way exactly this changes in sensibility appear.

Duration of the functional loss of the C- and A-delta-fibres after therapeutic application of capsaicin 8% as measured by the impairment of the thermal thresholds [ Time Frame: 8 weeks after capsaicin-patch (8%) application ] [ Designated as safety issue: No ]

measurement of thermal detection thresholds for warmth (WDT) and cold (CDT) by QST (standard DFNS protocol), change of z-values for WDT and CDT from baseline to 8 weeks after capsaicin-application (ANOVA)

Extent of the functional loss of the C- and A-delta-fibres after therapeutic application of capsaicin 8% as measured by the impairment of the thermal thresholds [ Time Frame: 8 weeks after capsaicin-patch (8%) application ] [ Designated as safety issue: No ]

measurement of thermal detection thresholds for warmth (WDT) and cold (CDT) by QST (standard DFNS protocol), change of z-values for WDT and CDT from baseline to 8 weeks after capsaicin-application (ANOVA)

change of dynamical mechanical allodynia measured by QST from baseline to 8 weeks after capsaicin-application

Correlation of efficacy on the sensory function and the reported soothing of symptoms after capsaicin-application [ Time Frame: 8 weeks after application of capsaicin-patch (8%) ] [ Designated as safety issue: No ]

comparison of z-values for cold, warmth and mechanical detection threshold to the outcome of the german versions of the following questionnaires: PainDETECT, NPSI (Neuropathic Pain Symptom Inventory) and Patient's global impression of change (PGIC), analyzed by ANCOVA

10 patients with neuropathic pain, because of peripheral nerve injury will obtain a baseline-QST and after capsaicin-application a QST 2, 4, 6, 8 and every 2 weeks until re-occurrence of pain and/or recovery of the capsaicin-induced sensory deficits

Procedure: quantitative sensory testing (QST)

with QST the small-fibre function is tested by registering thermal and mechanical thresholds, so that changes in the sensory profile can by specified

patients with postherpetic neuralgia

10 patients with neuropathic pain, because of postherpetic neuralgia will obtain a baseline-QST and after capsaicin-application a QST 2, 4, 6, 8 and every 2 weeks until re-occurrence of pain and/or recovery of the capsaicin-induced sensory deficits

Procedure: quantitative sensory testing (QST)

with QST the small-fibre function is tested by registering thermal and mechanical thresholds, so that changes in the sensory profile can by specified

Detailed Description:

The topical application of a high dosage of capsaicin (8%) is a new promising approach. There is only little knowledge about the extent and the duration of drug-induced changes of detection and pain thresholds based on a currently recommended standardized quantitative sensory testing (QST). The assessment of QST changes would be an important step forward to understand the way of action as well as the time course of the presumed recovering of the C-fiber function after topical application of a high concentration capsaicin patch.

10 patients suffering from peripheral neuropathic pain due to peripheral nerve injury and 10 patients suffering from postherpetic neuralgia will be investigated by QST following the protocol of DFNS (German Research Network on Neuropathic Pain), using both thermal and mechanical nociceptive as well as non-nociceptive stimuli.

QST will be performed at the following times:

at baseline

2, 4, 6, 8 weeks later, and every two weeks at least until re-occurrence of pain and/or recovering of the capsaicin-induced worsening of the C-fiber function.

some remaining sensory function at the baseline QST with z-scores ≥ - 3 for cold, warmth and tactile thresholds

Exclusion Criteria:

with missing informed consent

with any contraindications for capsaicin application

with diabetes mellitus,

using lidocaine patch in the test area in the last 6 months before enrollment

with inadequate knowledge of the german language

Contacts and Locations

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Please refer to this study by its ClinicalTrials.gov identifier: NCT01596491

Locations

Germany

Bergmannsheil, Department for pain management

Bochum, Germany

Sponsors and Collaborators

Ruhr University of Bochum

Investigators

Study Director:

Christoph Maier, Prof.Dr.med

University hospital Bergmannsheil department of pain management

More Information

No publications provided

Responsible Party:

Christoph Maier, Prof. Dr., Head of the Dep. of Pain Management, Ruhr University of Bochum